#macemulator

Testing Dark Castle with audio on the RP2350 Fruit Jam 🕹️🏰

Jepler spent a bunch of time this week working on getting audio working on the pico-umac port https://github.com/jepler/pico-mac/tree/rp2350-fruitjam to Fruit Jam

. Audio on the hardware we're emulating is pretty straightforward: every scanline of the video generator also pops out one byte of PWM data. We have 370 horizontal lines—352 visible and 18 during the vsync—and a 60.15 Hz refresh rate for 22.255 KHz audio approximately. That data is written to $1FD00 http://www.mac.linux-m68k.org/devel/plushw.php . That data is being piped over I2S to the MAX98357

and to a speaker for now.

So, of course, the first thing we have to try out is Dark Castle

Flap Flap Flying Toasters on Fruit Jam 🕊️🍞💾

We grew up with a Mac Plus/512K, so getting the Pico-Mac 68000 emulator https://github.com/evansm7/pico-mac working on Fruit Jam https://www.adafruit.com/product/6200 with 1MB+ of RAM was a high priority for those nostalgic vibes.

We've got HSTX DVI output plus PSRAM working https://github.com/jepler/pico-mac/tree/rp2350-fruitjam, which means 4MB RAM—that's the most you could get into a Mac Plus and enough to run System 6! https://en.wikipedia.org/wiki/System_6 Please note that System 7.1 was the pinnacle of software design, but System 6 was also pretty good. System 6 had some nifty features, such as the "Extensions" and "Control Panel" system programs, like After Dark with the famous Flying Toasters https://en.wikipedia.org/wiki/After_Dark_(software).

Note that we're still working on audio, so you can see the high byte of the memory space used for audio that we've mapped into the video RAM for visualization. http://www.mac.linux-m68k.org/devel/plushw.php has more details on how that works - its 8-bit PWM audio reads "one byte per scanline." We'll have that output on the I2S DAC for speaker or headphone output.